Hi, On Thu, 20 Apr 2006 08:05:50 -0500 "Johnson, Maurice E CTR NSWCDL-K74" <[EMAIL PROTECTED]> wrote:
> Need to find a better tutorial on initramfs. One that doesn't rely on > tools that automate the process. In fact, an initramfs doesn't differ much from other root fs'es. Physically, it is a gzipped cpio archive. The kernel will compile it into the kernel itself if you tell it so (kernel configuration: configure a patch for initramfs data). If you want to create it manually and load it like a ram disk (i.e. use the boot loader to pass the initramfs to the kernel) you can rely on a script that is in your kernels ./scripts/ directory and an executable that gets compiled in ./usr/ like this: gen_initramfs_list.sh /path/to/initramfs/data | gen_init_cpio /dev/stdin | gzip -9 > initramfs.gz Inside the initramfs you can create a userland. Kernel's entry point will be /init, which is supposed to be executable. You'll want to read /usr/src/linux/Documentation/early-userspace/README for the basics and then read /usr/src/linux/Documentation/initrd.txt (be careful to ignore the first part which is only initrd specific). You can put anything you want into your initramfs. If it's just some simple script that should be run, you're probably done with a statically compiled "busybox" executable and /init being a shell script. At the end of the script, you'll want to pivot_root into the real root filesystem and maybe delete initramfs data afterwards. I've never found really good documentation, but everything just works as expected. There's really nothing special with initramfs. Feel free to ask more questions here. -hwh -- gentoo-user@gentoo.org mailing list
